Directing vane



K. D. MOMAHAN 2,154,313

DIRECTING VANE Filed April 1, 1938 Inventor;

fins Attorney.

Kenton D .McMahan,

PatentedA r. 11, 1939 nmsomo VANE Kenton D. McMahan, Schenectady, N. Y., as-

signor to General Electric Company, a corpora- I tion of New York Application April 1, 1938, Serial No. 199,481

8 Claims.

The present invention relates to directing vanes for directing the air stream from propeller fans and the like.

The air stream moved by propeller fans is in the form of an axially moving column of air" which has a velocity distribution in an axial direction which is a minimum at the center and increases to a maximum or peak velocity at a point near the outer surface. From this point v m the velocity decreases to substantially zero at the outer surface of the air column. In addition -to the axial velocity'the air column also has a rotational component produced by the fan blades. For some purposes, for example when the air 1| column is directed through a heat exchanger, it is desirable that the rotational component of the air be removed. It is also desirable that the variation in thevelocity distribution be decreased. so The object of myinventionis to provide an improved construction in directing vanes which will convert the rotational component of an axially moving column of air to an axial component in such a manner as to decrease the variation in as velocity distribution. 1

In the accompanying drawing, Figure 1 is a sectional end elevation of a propeller fan equ ped with directing .vanes embodying my invention; Fig. 2 is a front elevation of the directso ing vanes; Fig. 3 is a side elevation of one of the vanes; Fig. 4 is an edge elevation of one of the vanes; Figs. 5, 6 and 7 are sectional views taken on-lines H; 8-! and ,I--'| of Fig. 4. Referring to thegdrawing, there is shown a '5 propeller fan having blades l of the construction shown in my Patent No. 1,964,525, issued June 26, 1934. 'Theblades are attached to a hub 2 which is rotated in a clockwise direction, as viewed in Fig.- 2 by suitable (not shown). 40 The fan blades are within a cylindrical housing '3 having an outwardly flaring rear edge 4 which provides an intake orifice for guiding the air to the fan blades. Within the front edge of the casing 3 are radially extending vanes 5. The outer 5 edgesgof the vanes are fixed to segmental plates 8 having forward edges I. extending over and riveted to the rear edge t of the succeeding segment. when assembled, the segmental sections 6 provide a ring which is securedto the inner 50 surface of the casing. At the inner edges the vanes 5 are fixed to anannular ring or hub 9. The front edges ll ofjthe vanes are presented to the air stream of the fan. As shown in Figs. 5, 6 and 7, these edges are rounded so as to provideaniinimumoiinterferencewiththeair.

.' The faces of the vanes extend axially providing passages therebetween through which the air column flows. At the front edges Ill, the faces extend at substantially the angle in which the air stream is moving so as to reduce the losses 5 due to impact of the air stream with the edges Ill. The direction in which the air stream moves is that resulting from the summation of the axial velocity component and the rotational component. 10

The axial component of the air column flows between the vanes substantially without change. The rotational component of the air impinges against the front faces ll of the blades and is deflected in an axial direction. By converting is the rotational component of the air into an axial component the efllciency is increased since otherwise the energy contained in the rotational component would be dissipated in eddy currents. As shown in Figs. 5, 6 and 7 the front faces of the l) blades are concave in an axial direction. In other words, the rear edges I 2 of the vanes extend substantially axially while the frontfaces I I are curved axially with gradually increasing curvature toward the front eglges It in a direction op- 'posite to the rotation of the rotational component of the air. By this means the rotational component is more gradually converted to an axial component.

If the rotational component of the air column so were merely changed to an axial component the velocity distribution throughout the air column would remain substantially unchanged. There would merely be an increase in efiiciency due to the conversion of the rotational component into an axial component. For this reason the blades do not extend directly radially outward from the hub 9. From the hub to region l3, which is located in the region of maximum or peak velocity, the vanes extend radially backward as regards 49 the direction of-rotation of the rotational com-' ponent of the air -column. From the region iii to the periphery, the vanes extend radially foraward. From the hub 9 to the region IS the vanes cooperate-with therotational component of the air to deflect it axially and radially inward. From the region 13 to the outer ends the vanes cooperate with the rotational component to deilect-it axially and radially outward. As regards the rotational component of air, the surfaces of 0 the vanes may be described as radially convex in that the bladespresent convex surfaces opposed to the rotational component of the air. By this means the rotational component of the air is converted into axial components deflected radialvanes utilize the rotational component to affect this change in velocity there is a substantial increase in efliciency. In actual practice increases inefiiciency of more than ten per cent have been obtained. There has also been an increase in the air flow of the fan due to the decrease in resistance offered to an air stream having a more uniform velocity distribution.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. Directing vanes for a column of air having a rotational component about the axis of flow and a velocity distribution varying with the radial distance from the axis of flow, comprising circumferentially spaced radially extending vanes having edges presented to the axial moving air and having faces extending axially, the faces of the vanes in a radial direction being conversely opposed to the rotational component of the air and cooperating with the rotational component of the air to deflect it axially and radially whereby the rotational component of the air is converted to an axial component decreasing the normal variationin velocity distribution 2. Directing vanes for a column of air having a rotational component about the axis of flow and a velocity distribution increasing radially to a maximum at a region of peak velocity and decreasing therefrom radially to a minimum velocity at the outer edges, comprising circumferentially spaced radially extending vanes having edges presented to the axially moving air and having faces extending axially, the faces of the vanes radially inward from the region of peak velocity being inclined radially backward as regards the direction of rotation of the rotational component of the air stream and the faces of the vanes radially outward from the region of peak velocity being inclined radially forward as regards the direction of rotation of the rotational component whereby the rotational component is deflected axially and radially outward and inward so as to decrease the variationin velocity distribution of the air column.

3. Directing'vanes for a column of air having a rotational component about the axis of flow and a velocity distribution increasing radially to a maximum at a region of peak velocity and decreasing therefrom radially to a minimum velocity at the outer edges, comprising circumferentially spaced radially extending vanes having edges presented to .the axially moving air and having faces extending axially, the faces of the vanes in the region of peak velocity being convex in a. radial direction and cooperating withthe rotational component to deflect it axially and radially outward and inward whereby the rota tional component of the air is converted to an axial component decreasing the normal variation in velocity distribution.

4. In combination, a propeller fan, radially extending vanes in front of the fan having edges presented to the axially moving air stream and faces extending axially,- the faces of the vanes in the region of peak velocity being convexly opposed in a radial direction to the rotational component of the air whereby the rotational component of the air stream is deflected axially and radially so as to change the velocity distribution of the air stream.

5. In combination, a propeller fan, circumferentially spaced radially extending vanes in front of the fan, the edges of the vanes being presented to the axially moving air stream and the faces of the vanes extending axially, the faces of the vanes being convexly opposed in a radial direction to the rotational component of the air and cooperating with the rotational component of the air stream to deflect it axially and radially whereby the velocity distribution in front of the vanes is changed.

6. In combination, a propeller fan, circumferentially spaced radially extending vanes in front of the fan, the edges of the vanes being presented to the axially moving air stream'and the faces of the vanes extending axially, the faces of the vanes in the region of peak velocity being inclined radially forward and backward with regards-to the direction of rotation of the rotational component whereby the rotational component is deflected radially outward and inward as it is changed to an axial component so as to decrease the variation in velocity distribution of the air column.

7. In combination, a propeller fan, radially extending vanes in front of the fan having edges presented to the axially moving .air stream and faces extending axially, the faces of the vanes radially. inward from the region of peak velocity being inclined radially backward as regards the direction of rotation of the rotational component of the air stream and the faces of the vanes radially outward from the region of peak velocity being inclined radially forward as regards the direction of rotation of the rotational component of the air stream.

8. In combinatio a propeller fan, circumferentially spaced radially extending vanes in front of the fan having edges presented to the axial moving air stream and faces extending axially, the faces of the vanes in the region of peak velocity being radially convex and cooperating with the rotational component of the air stream to deflect it axially and radially outwardand inward so as to decrease the variation in velocity distribution. a

' KENTON D. McMAHAN.

CERTIFICATE OF comcnon. Patent No. 2,15L 1 April 11, 19 9.

' KENTON D. McMAHAN.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, first column, line 21, claim 1, for "conversely" readconvexly; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 6th day of June A. D. 19 9.

Henry Van Arsdale (Seal) v Acting Comnissioner of Patents. 

